1. Field of the Invention
The present invention relates to a refrigerant compressor for use in electric refrigerators, air conditioners, heat pumps or the like apparatus.
2. Description of the Prior Art
The refrigerant compressor of the type mentioned above usually has a closed casing accommodating a compressor section and a driving motor section constructed as a unit with each other. In operation, the lubricating oil collected at a lower portion of the closed casing is sucked up and forcibly supplied by a lubricating system to various rotating and sliding parts such as crank shaft, bearings and so forth to ensure a smooth compression of the refrigerant.
For instance, U.S. Pat. No. 3,317,123 issued to L. F. FUNKE proposes a refrigerant compressor in which the lubricating oil supplied by the lubrication system is introduced to the portions of the compressor requiring lubrication, through an oil passage formed in the crank shaft and then through branching passages communicating with the oil passage formed in the crank shaft. In this type of lubrication system, the lubrication oil comes up to the eccentric portion of the crank shaft by the action of the centrifugal force and then forcible charged to the main shaft portion of the crank shaft corresponding to the electric motor. It is quite difficult to forcibly charge the lubricating oil from the eccentric shaft portion to the main shaft portion from the eccentric shaft portion, because the centrifugal force in this case acts to resist to the flow of the lubricating oil. This problem is serious particularly when the lubricating oil contains gaseous refrigerant.
The U.S. Pat. No. 2,669,384 issued to R. L. DILLS proposes a lubricating system having an oil groove formed in the outer peripheral surface of the crank shaft, so that the lubricating oil supplied by the lubricator is introduced through the oil groove to the portions of the compressor requiring lubrication. In this lubrication system, the oil groove has to have a quite long length. A considerable labour and cost are required for machining such a long oil groove.
In these known refrigerant compressor, it is necessary to use a lubricator capable of delivering the lubricant at a sufficiently high pressure and large flow rate, for otherwise it is not possible to supply the lubricant to the portions requiring lubrication through the oil passage or oil groove.